Conventional size adjustment mechanisms for headwears or sun visors include size adjustment mechanisms that use a belt and comprise an adjuster and a rail, American hook-type size adjustment mechanisms, and hook-and-loop fastener-type size adjustment mechanisms.
In the size adjustment mechanisms utilizing an adjuster and a rail, the adjuster is slid on the rail to adjust the size. These mechanisms are seldom used at the present time. In the American hook-type size adjustment mechanisms, a belt having about 7 holes formed therein is used in combination with a hooked belt to allows the size to be adjusted by shifting a position for fitting into the hole.
The use of hook-and-loop fasteners can allow belts to be prepared using the same cloth as used in the front cloth and thus can prevent loss of the texture of a cap body. The hook-and-loop fasteners, however, are generally weak against rain water and moisture. Further, dust or the like is likely to adhere thereon, sometimes leading to lowered bonding strength.
On the other hand, a method for size adjustment has also been proposed that does not use any belt and adopts a rubber as a material for a sweatband or a part of the sweatband in a cap. When the whole sweatband is elastic, there is a possibility that functions as the sweatband such as sweat absorption, quick drying, and deodorization are deteriorated. When rubber is used in a part of the sweatband, it is necessary to provide tucking to the cap body or to use a stretchable cloth. Further, the bonding strength of the rubber undergoes a significant aged deterioration and thus is likely to be significantly lowered.
Patent document 1 (Japanese Utility Model Application Laid-Open No. 168536/1983) discloses a free-size cap in which a band piece and a band piece-locking tool are interposed between a cap body and a sliding material provided on the inner side of the cap body to improve an appearance of the cap and a flexible foam sheet is internally provided as a core material in the sliding material to improve cap wearing comfort. In patent document 1, however, any consideration is not taken for attachment of the locking tool to the cap body, posing a problem that a stopper for release of locking is hit against the cloth constituting the cap body, resulting in unintentional release of locking.
On the other hand, patent document 2 (Japanese Utility Model Registration No. 3005659) discloses a size adjustment mechanism that can realize size adjustment in a cap worn state and, at the same time, can realize fine adjustment. The size adjustment mechanism disclosed in patent document 2 is likely to require an increased device size, and, thus, a restriction on design is increased for the attachment of the device to the cap. Thus, the size adjustment mechanism is impractical. Further, there is a possibility that, when the cap falls, the device is broken. Difficulties are encountered in attaching this device to sun visors, of which the area where the device can be attached is small.
The present inventor has previously proposed a slide adjuster usable for apparel such as headwears, trousers, or skirts in which a great importance is attached to design of appearance. The slide adjuster comprises a band and a buckle, an engagement claw in the buckle being engaged with a serrated engagement groove provided on an outer surface of the band so that, in an engaged state, the band freely approaches the buckle but cannot retract, wherein the buckle comprises: a buckle body comprising a bottom plate and a ceiling frame facing each other and two side plates for connecting the bottom plate to the ceiling frame, the inside of the buckle body functioning as a band insertion space; and an operating plate that is horizontally provided on the inner side of the ceiling frame, has, on an under surface at one end thereof, the engagement claw engageable with the engagement groove in the band, the other end functioning as a pressing part for the release of the engagement, and wherein the operating plate is supported by a connecting shaft between the two side plates at an intermediate point between the engagement claw and the pressing part to allow the operating plate to be swingable at the intermediate point as a fulcrum, and a pair of latch protrusions is provided on the outer surface of the band and the pressing part to allow the buckle and the band to be pulled by a fingertip in one hand (Japanese Patent No. 4005109: patent document 3).